parseFloat and if then statement

I am trying to construct a simple input text box that is checked by a button. If the student types in 1077.63 he should get a “correct” message, and if not, an “incorrect” message. The problem is that I can’ t get AS to recognize the 1077.63. It will work when I use 177.63, 100.63, 7000.63; or what seems like ANY other number other than one I need! The code I’m using is listed below.

on (press)
var a = a_txt.length ? parseFloat(a_txt.text) : 0;
if (a==1077.63) {
feedback = “Yes, you are correct.”;
setProperty(equation, _visible, true);
} else {
feedback = “No, that is incorrect.”;

[AS]setProperty(equation, _visible, false);
a_txt.restrict = “0-9.”;